In the color filter process of thin film transistor liquid crystal display (TFT-LCD), after applying the photoresist with a coating machine, a prebake equipment is usually used to further remove the solvent for the photoresist and enhance the adhesive force between photoresist and substrate, so as to avoid the defect in the exposure area resulted from the detachment of the film due to the insufficient adhesive force when developing. During the operating process of the prebake equipment, organic sublimates will be generated within the cavity of the prebake equipment, resulting in an increase of the particles inside the cavity which will influence the quality of the products. Therefore it is necessary to discharge air from the cavity during the operating process so as to improve the rate of good product and facilitate the maintenance of the equipment.
In the prior art, in an prebake equipment without a hot air system, the air discharge is generally performed after the termination of the operating process, resulting in a short discharge time and a limited removal rate of organic sublimates from the cavity, and a big gap in the effect of sublimates removal as compared to air discharge during the operating process (an removal ratio in the air discharge during the operating process to that not during the operating process is generally above 14).
To improve the effect of air discharge, prior art usually needs an additionally mounted hot air system, adopts clean dry air (CDA) as air source, and heats the air by using a heating unit, so as to achieve an air discharge during the operating process. Although such a method has a good effect for removing sublimates, the cost for equipments is increased (for example, ducts and the heating unit), the energy consumption of hot air system (electrical energy and air) is large and it is very inconvenient for daily maintenance of the equipment.